The flight level at which an aircraft flies can affect fuel consumption, emission rates, and other measures of aircraft performance. It is thus desirable to enable aircraft to frequently and freely transition flight levels as conditions, such as wind conditions and turbulence levels, vary at different flight levels. When an aircraft transitioning flight levels does so in the presence of nearby aircraft occupying an intervening flight level, the transition in flight level is commonly referred to as an “In-Trail Procedure” or, more simply, an “ITP.” ITP protocols have been established to ensure safe and efficient transition in flight levels in the presence of aircraft traffic in non-radar regions, such as oceanic or remote airspace. Generally, under ITP protocols, the pilot or other aircrew members onboard an aircraft desiring to transition flight levels are required to ensure that a number of ITP criteria are satisfied before requesting clearance from an Air Traffic Controller (“ATC”). Such criteria may include the reception of qualified Automatic Dependent Surveillance Broadcast (“ADS-B”) data from neighboring aircraft (commonly referred to as “reference aircraft”) to ensure that minimum ITP separation requirements and maximum ground speed differential thresholds are not exceeded. The aircraft may then request clearance for the flight level change from the ATC. After confirming that a number of additional ITP criteria have been satisfied, such as the absence of nearby aircraft that could potentially block the ITP procedure, the ATC clears the aircraft for the change in flight level. The pilot of the aircraft then performs the ITP procedure without undue delay.
To assist in identifying and performing ITP maneuvers, flight deck display systems have been developed that generate a so-called “ITP window” on a cockpit display or monitor. The ITP window is typically a two-dimensional vertical representation of the airspace surrounding the aircraft equipped with the flight deck display system at issue (referred to herein as the “ownship aircraft” or the “host aircraft”). The ITP window may include symbology representative of the flight level occupied by the host aircraft, several flight levels above and below the flight level occupied by the host aircraft, and any neighboring aircraft (referred to herein as “intruder aircraft”) within the vicinity of the host aircraft and meeting certain other criteria (e.g., aircraft traveling along a similar track as the host aircraft). By glancing at such an ITP window, a pilot can quickly form a mental picture of his or her surrounding environment and gain the information required to ensure a safe change in flight levels or, at minimum, to determine that a request to transition to a particular flight level is likely to be approved by the ATC. However, ITP windows generated by flight deck display systems remain limited in certain aspects. For example, and without implication that any such limitations have been recognized in the prior art, conventionally-generated ITP windows generally do not provide a pilot with readily comprehendible manner in which to predict future transitions in flight level by intruder aircraft and thereby determine in advance whether a transition to a soon-to-be-vacated flight level might be warranted.
It is therefore desirable to provide flight deck display systems and methods for generating ITP windows including symbology providing an enhanced situation awareness to a pilot and other aircrew members prior to and during an ITP event. It would be particularly desirable for such ITP window symbology to provide an intuitive and readily comprehendible visual queues as to the likely intent of intruder aircraft in transitioning or maintaining current flight levels, as well as to the current and future positioning of the host aircraft relative to nearby intruder aircraft during an ITP event. Other desirable features and characteristics of the present invention will become apparent from the subsequent Detailed Description and the appended Claims, taken in conjunction with the accompanying Drawings and the foregoing Background.